THE DEFECT CHEMISTRY OF LAMNO3+ -DELTA .3. THE DENSITY OF (LA,A)MNO3+DELTA (A=CA, SR, BA)/

The density of La1-xAxMnO3+delta was determined for x = 0,0.15, 0.30 ( A = Ca, Sr, Ba) and for x = 0.50 (A = Sr) using a pycnometer, defect c hemical considerations, lattice parameters, and chemical analyses. The oxygen excess in LaMnO3+delta is compensated by both La and Mn vacanc ies in equal amounts. This is confirmed by density measurements. Accor ding to this defect model the density of LaMnO3+delta, is almost indep endent of delta for 0 less-than-or-equal-to delta less-than-or-equal-t o 0.18 and is calculated to be (6.57 +/- 0.02) g . cm-3. The same defe ct model is applied to calculate the density of La1-xAxMnO3+delta. (C) 1994 Academic Press, Inc.